1. Field
One embodiment of the present invention relates to an electronic device having a printed circuit board provided with an electronic component that generates heat, and more particularly to an electronic device provided with a rotation preventing structure that operates when a heat sink is attached to the electronic component.
2. Description of the Related Art
In general, a heat sink made relatively large to exhibit a high heat dissipation efficiency is provided on a heat-generating electronic component, such as a CPU, mounted on a printed circuit board in an electronic device. The relatively large heat sink inevitably increases the size of the entire device.
To avoid this, a heat dissipation structure for heat-generating electronic components, which is made compact and thin without changing the size of the heat sink incorporated therein, has been developed by contriving the way of attachment of the heat sink to the printed circuit board (see, for example, Jpn. Pat. Appln. KOKAI Publication No. 2004-228529, paragraph [0006], and FIG. 3).
In the disclosed heat dissipation structure, a relatively large notch is provided at one end of a printed board 4, and a heat sink 2 with a heat-generating electronic component 1 attached thereto is made to cover the notch so that an auxiliary heat sink 5 attached to the lower surface of the heat sink 2 is received in the notch, thereby channeling the heat of the electronic component 1 to the main body 8 of the tool provided on the reverse side of the printed board 4.
When the disclosed heat dissipation structure, in which the heat sink 2 with the heat-generating electronic component 1 attached thereto is made to cover the notch of the printed board 4, and the auxiliary heat sink 5 is provided in the notch, is employed, no structure projects from the outline of the printed board 4 and hence the entire device can be made compact.
However, in the disclosed case, it is necessary to form a relatively large notch at one end of the printed board 4. This reduces the space for mounting other electronic components or for wiring, which is disadvantageous to currently rapidly advanced high-density mounting. Further, in the disclosed structure, a groove 14 to be engaged with a claw 13 projecting from the heat sink 2 is also formed in the inner edge of the notch of the printed board 4 to prevent the member 2 to rotate when the member 2 is screwed to the main body 8. The existence of the groove makes it further difficult to design the printed board, i.e., to realize high-density mounting.